Process of producing combustible gas and for carbonizing coal



H. L. DOHERTY.

PROCESS 0F PRODUCING COMBUSTIBLE GAS AND F03 CARBONIZING COAL.

APPLICATION FILED SEPT. 7, 19H3.

Patented Aug. 1.5, 1922.

4 SHEETS-SHEET l.

@num/Ufo@ H. l.. DOHERTY.

PROCESS OF PRODUCING ACOMBUSTIBLE GAS AND FOR CARBONIZING COAL.

l APPLICATION FILED SEPT. T, l9|8 3,426, l 59..

t Patented Aug. 15, 1922.

' 4 SHEETS-SHEET 2- 76 nmm Hq/IUDYMQU;

H. l.. DOHERTY.

PROCESS 0F PRODUCING COMBUSTIBLE GAS AND FOR CMTBONIZING COAL.

AFPLICAUON FILED SEPT. 7, 1918- l ,426,159.

Patented Aug. 15, 1922.

4 SHEETS-SHEET 3.

. DOHERTY.

PROCESS 0F PRODUCNG COMBUSTIBLE GAS AND FOR CARBONIZING COAL.

APPLICATION FILED SEPT. 7, l-9l8.

Patented Aug. 15,A 1922..

4 SHEETS-SHEET 4.

HENRY L. noHERTY, or NEW YORK, 'N'. Y.

PROCESS F PRODUCIN G COMBUSTIBLE GAS AND FOR CARBONIZING COAL.

To all @cham z'tmy concern.'

Beit known that I, HENRY L. I )oHERrY, a 'citizen' of the United States, residing at New -Y`ork city, -in the county of New York, State of NewYork, have invented certain new and useful Improvements -.in Processes of Producing Combustible Gas and lfor Carbonizing Coal; and I do hereby declare the following to be 'a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to'make and use thewsame.

This invention relates to a process of producing combustible gas and for carbonizing coal. .1.

A' large proportion of the gas manufactured for domestic consumption in this coun'- try contains a large percentage of what is commonly known as blue water gas. Blue water gas is made by passing steam throughan incandescent bed of coke to del carbon monoxide.

compose the steam and form hydrogen and Carbon dioxide is -always formed in the production of water gas and the gas-making operation is generally controlled by maintaining a deep fuel bed and comparatively high temperatures to produce a minimum percentage of carbon dioxide and a maximum percentage of carbon monoxide. Vater gas is made in two stages, the first stage being a blasting stage to raise the temperature of the fuel bed sufficiently high-to decompose steam, and the second stage consisting in passing steam into contact with the heated fuel bed to', form gas. The fuel y bed is usually supported on removablegrate bars and the entire bed is heated by blasting air upwardly therethrough. The air is introduced cold into the fuel bed to avoid burning out the grate bars and the products of combustion leave the fuel bed in a highly heated condition and often carry combustible gases out of the furnace. In the gas-making operat-ion, steam isvintroduced into the bottom of the fuel bed and the gas 'leaving the top of the furnace from the fuel bed is veryy hot and has to be cooledbefore it can be purified. These operations-cause' the loss of ,u vention is to provide a process for making a large amount of heat andmateriallyvdecrease the efliciency of the process;

The primary object of the present 1nl Specification of Letters Patent. Patented Aug. 15, 1922.

Application filed September 7, 1918.

Serial No. 253,045.

manufacture of coal distillation gas. rl`he claims of the above patent are directed broadly to a process of carbonizing coal While producing gas, and some of the more specific claims are directed to a process of carbonizing coal and producingl a distillationof coal gas. The claims of the present application are directed to a process of lproducing water gas.

In the process of carbonizing coal .described in my patent above referredto, coal4 is passeddownwardly in a column through a shaft furnace and a hot mid portion is formed in the column by intermittently blasting air transversely through it.. lBetween the blasting operations, gas is circulated upwardly through the column, which acts to absorb heat from coke in the column as it advances toward the hot mid portion and acts to supply heat *for distillation of coal in the column as it advances away from the hotv c mid portion. Some of the volatile materials distilled fromV the coal condense in the upper portion of thev fuel column in the form of taror oil and'y when` the circulation of gas upwardly through the fuel column is stopped during the blasting operation, there is a tendency for the tar to run down into the' hot mid zone. vIf an excess of tar reaches the hot mid zone, it will4 quench the hot fuel and tend to clog the fuel bed so that it'is diicult to force an air blast through the bed. Further, the tar coming into contact with the hot fuel, is decomposed with a heavy deposition of Ocarbon black, some of which is carried out of the furnace and into the heat regenerators by the blast exhaust products.

Accordingly, anotheriobject of the present invention is vto provide a process of producclaimed. A

ing gas from coal in which a hot mid zone of and 4,apparatus for producing gas and.

carbonizing coal hereinafter described and 'v The various features ofthe invention are illustrated in the accompanying drawings, in which Fig. 1 is a View in side elevation of a gas-producing furnace and its auxiliary gas-.treating apparatus .embodyingv the preferred form of the invention;

Fi 2 is a view in vertical section taken on l the l1ne 2 2 of Fig. 1, of the gas-producing v l y y1n a comparatively cool state. By means of .theintermittent cross blast and the inter- Fig. 3 is a v iew in hoizontalsection on the line 3-3 of Fig. 2 of the gas-producing furnace', one of the heat regenerators `being broken away; l

Fig. 4 is a detail view in vertical' section showing the upper portion of the refractory lining of the furnace;

Fig. 5 is a view 1n horizontal sectionfof coke-discharging scra er in plan; and

, the lower end oftlfurnace showing lthe Fig. 6 is aview in si ri elevation, ,partly inl section, showing the fue -charging bucket `in position over the fuel-charging opening of the furnace. To carry out the improved process in the apparatus .illustrated in the' drawings,-fuel isY passed in a column downwardly through a shaft furnace 10 (Fig. 2), the fuel being intermittently admittedI to' thefurnace through a charging opening l2 and intermittently Ydischarged 4from the furnacev through an outlet gate 14. Gas is produced from the fuel in two distinct operations, namely, a blowing or heating operation and a gas-making operation. ln the blowing operation, air is blasted through the fuel column b`y means of a blower 16 (Fig. 1). The air from the blower' passes through conduits 18 into the base ofvone of a pairfof regenerators 20 or 22, then hows up. through the regenerator, and passes through a horizontal flue 24 or 26 into a mid-portion of the fuel column. The blastexhaust gases pass out of I the fuel'- column very hot and-flow through one of the iues 26 or 24 into one of the heat 'regenerators' 22 `or 20 where the heat is `absorbed from the gases and the gases exhaust comparatively cool through outlet pipes 30 or'28. When the heat of the exhaust gases has .'built up the temperature .of one regenerator, the incoming air Vfrom the blower v16 is reversed by valves 32 or 34 to admitftheair through the heated regenerator and ex'- haust the air through the regenerator prel viously used for preheating the air. The fuel column is blown intermittentlyand the direction of the blasting gas is generally re-v in the. column. rlFhe gas enters the fuel column in a comparatively cool condition and v umn countercurrent to the movement of fuel acts "to absorb heat from the coke in the lower portion of the fuel column and carry theheat toward the hot mid portion. After i theg'as passes through the hot mid portion,

it acts to 'impart heat to the fuel in the-uppery portion of the column and leaves the column bustion zone 38, a coal-distilling and tarcondensing zone 42 at the upper end of the ^column, and a coke-cooling zone 44 eXtending from the combustion zone 38 to the bottom of the column.. With a careful regulation of the cross blast air, the heat-transferring gas vand the passage of the fuel downwardly lthrough the furnace, the temperature in the fuel column may be controlled so that the fuel will enter and leave the column in a comparatively cool state, the gasesl passing upwardly through the fuel co'lumn will enter and leave the fuel column in a com paratively cool state, and the cross blast air will enter and leave the heat regenerators in a comparatively cool state. ln these operations, therefore, heat is always carried toward the hot mid portion of the fuel column, the heat being recuperated vfrom the products being removed from the furnace, and utilized in the carbonization of coal and the production of gas.

rlhe gas' produced from the fuel and steam, together with the heat-transferring gas which may pass through the fuel column, are removed from the' upper-end of the furnace through an outlet 46 into'a main 48 and pass into a water condenser 50 (Fig. 1)'. From the condenser 50 the gases pass through a conduit 52 into a scrubber 54,

then through a conduit 56 into a purifier 58 and through a conduit 60 into a gasholder 62. A portion of the gas advancing 'to the holder 62 is removed'from the'conduit- 56 through a valve 64 into a conduit 66 and is forced by a blower 68 through a water-absorber 70. The water used in the absorber 70 consists of the water which has been previously heated in the condenser 50 and flows from the condenser through a pipe 72 into the upper portion of 'the absorber. The increased temperature of the water over that of the incoming gas increases the temperature of the gas and results in a large amount of water vapor being carried out with thel gas. The gas-water-vapor mixture v from the absorber 70 passes Ainto a conduit 74 which'is connected to the furnace gas inlet 36. In case the gas produced in-the furnace 10 contains products which will be decomposed or lost when the gas passes through the hot mid portion 38, it may not be desirable to use a. portion of the gas produced as a heat-transferring medium but a gas may be obt-ained from another source. If desired, the gas circuit through the blower 68 can be cut out entirely and live steam can be admitted through a valve 76 in the conduit 74 as the heat-transferring medium.

The sha-ft furnace 10 is arranged `to V,sup-

port the fuel in a vertical column in hsuch a manner that the fuel may be continuously f advanced through the furnace while gas is being intermittently produced'and coal `iI1 the fuel is being carbonized. The furnace 10 (Fig. 2), consista cylindrical gastight metal shell 78 pro ided with a refractory lining 8() and havin a top cover 82 in which the charging opening 12 is located and a coke-discharging hopper 84 at its lower end in which the discharge gate 14 is positioned. The refractory lining 8() is positioned only in the central portion of the inner surface of the shell so that the upper and lower ends of the fuel column normally project beyond the lining. The lining 80 is supported at its lower end upon a plate86 which is mounted upon the upper ends of columns 88 which supportthe metal shell 7 The upper end of the refractory lining 1s constructed to form a restricted opening for 'the pass,age of fuel through the coal carthe hot mid zone 38.

bonlzing zone 40 and thel restricted passage extends down to the upper end of the hot combustion zone 38 (Figs. 2, 3 and 4). Below the restricted passage the lining conformsto the shape of the-shellg78to increase the cross-sectional area`of'the fuel column so that the coal may `expand into a larger space to be in an open condition to assist the cross blast in penetrating through the column. Fire arches 90 and 92 are arranged to forni the lower portion of each side of the restricted passage immediately in front of the blast air flues 24 and 26 and serve to Adirect the cross blast downwardly into These fire arches confine the cross blast to the mid zone 38 and prevent a direct application of the cross The fuel in the combustion zone 38 consists mainly of coke and when the blast gases pass through the lmid zone, the coke is burned to produce carbon dioxide. The temperatures of the coke in the mid zone are very high and the fuel bed usually has such a thickness that the differential pressures, which may be practically used for driving the blastair, will not entirely prevent the formation of some carbon monoxide by the decomposition of carbon dioxide within the fuel bed. This carbon monoxide, therefore, will pass out through one of the iues 24 or 26 into the corresponding regenerator. To insure that all of the heat in the exhaust gases leaving the fuel bed (heat of combustion as well as sensible heat) may be removed in the regenerators 2O and 22sulicient secondary air is led from the passages 24 or 2,6 around the fuel column to burn the carbon monoxide carried out of the fuel yThe adjustment of the valves 96 is su'ch that only suflicient secondary air will be conducted around the fuel column through the iues 94 to burn the carbon monoxide emergingfrom the fuel column with the blast gases.

" To protect the fire arches and the refractory lining from the high temperatures developed in the combustionof the coke in the hot mid Hso.

Zone and the combustion of the carbon monoxide, a carborundum facing is attached to the refractory lining and lire arches in the vicinity of. the hot midzone.

The regenerators 20 and 22 for preheating i the cross blast air and for absorbing the heatfof the cross blast exhaust gases consist of cylindrical gas-tight shells 104 (Figs. 2 and 3) which have refractory linings 106 covering their inner surf-aces. The heat recuperation of the gases in the regenerators is effected mainly by means of a series of checker bricks 108, which are supported on grates 110 positioned near lthe bottom" of the shells 104,` and extend up to the` level of the flues 24 and 26. To permit access to the top of the regenerators, manholes 111 are placed at the upper end of the regener-ator shells. These manholes are normally closed and peep-holes 112 are arranged therein to per- `mit inspection of the interior of the regenerators. Manholes 113, similar to manholes the regenerator. To permit the removal of this materialwithout stopping the operation of the regenerators,dirt traps 114 are positoned at the bottom of the regenerators. The traps arev formed in the concrete foundations of the vregenerators and consist of vvertical passages 116 positioned approximately in the center of the regenerators and inclined cleaning passages 118 connecting with the bottoms of the passages 116 and ex.- tending up to the outside of the regenerators.

' Afluid such as water is maintained in the trap to make a gas seal tov prevent the escape of gases from the regenerator. dirt from the interior of the regenerator collects inthe bottom of the traps and may be removed with a hoe through the passa-ges 118. The traps 114 also serve as emergency exits for gas to prevent damage from an explosion in the regenerator or furnace. y The blast air enters the bottom of the regenerators through the conduits 18 (Fig. 2) which connect with the vertical passage 116 of the traps 114. `Vlhen air is led into the regener-ator 2() (viewing Fig..2) through the valve 32, the valve 34 is closed and the air. passes up through the regenerator 2() to the flue24, through the fuel column to the flue 26,' down lthrough the regenerator 22, and out. through the exhaust pipe 30 -to the atmosphere.` During this operation, the eX- haust pipe 28 of the regenerator 20 is closed by a gate 120 (Figs. 1 and 2), which is hinged to a collar 121 secured to the upper end of the exhaust pipe. To make a gastight seal of the pipe 28 with the gate 120, a yoke 122 is pivotedto the collar 121 and connected to the gate 120-by means of a pressure link 124.l The pressure .link and yoke form a toggle whichlwill force the gate 120 into Contact with the collar 121 with sufficient pressure to seal the pipe 28 when the toggle is straightened. By moving the yoke 122 to the left viewing Fig. 2), the toggle will be broken to relieve the pressure of the gate 'on the collar and a continued movement, of the yoke will act tol swing the'v gate around its hinge.r 'llhe eX- haust pipe 30 is provided with a gate 123` similar to the gate 120 and these gates are ,'operated to close the exhaust pipes of their respective regenerators at the time the regenerator is being used to preheat the blast air and to open the exhaust pipe when 'the .regenerator is used to absorb the heat of the `exhaust blast gases.

To distribute the heat-transferring gas p i' uniformly throughout the area of the fuel column, the gas isled into the lower end The ofthe fuel column aroundthev entire periphery and through the bottom. 'llo accomrumn, the column is supported by a conical deflector 130 and an annulus plate 132. The deflector 130 consists of a series of perforated plates shaped to form a cone,'which are supported upon a series of bars 134 secured to the apron l126. The peripheral edge of the deflector 130 is spaced from the apron 126 to provide a discharge opening l131 for the fuel of the column and the annulus plate 132 is supported, on lli-beams 133 secured to the .columns 88. rll`he plate 132 islpositioned below the` discharge opening 131 arsufficient distance to permit the fuel to spready out upon the plate and has sufficient width to su port vthe fuel at its angle of re ose so that the fuel will not run out of t e column without being positively removed from the plate. The gas from the hopper 84 passes up through the perforations in the cone 130 and also into the discharge opening 131 through the loose coke on the plate 132. Since the lower end of the fuel column is comparatively cool, the parts for supporting it may be constructedof metal.

To discharge the coke from` the supportf ing plate 132, a scraper136 (Figs. 2 and 5) is mounted .upon the plate 132 and arranged to be reciprocated acrossthe plate to discharge the coke through the central opening, 138 of the plate and over y the outer edge. The scraper 136 consists of a circular angle iron which rests on a wear-plate 140 secured to the upper side. of the plate 132. rllo reciprocate the scraper on the sup- Y 'porting plate 132, a pivot block 142 is mounted at the center of the' scraper on tie-rods 144, and a` pivot pin 146 in the block 142 is connected with links 148 which collects in the -hopper 84 above the .dis-A charge The coke discharged from theV plater132 gate 14. When the hopper becomes v filled with coke, the discharge gate is opened to permit the coke to run out and during this operation steam is admitted into the hopper through a pipe 154 to prevent air from entering the hopper through the discharge opening. The discharge gate 14 consists of a metal cover which is hinged to a collar 156 secured to the lower end of the hopper 84. 'A toggle vmechanism similar to the toggle 122-124 is used for operating the gate 14 which is arranged to swing the gate about its hinge and to force. the gate into pressure engagement with they collar 156 to maintain a gas-tightseal for the discharge hopper.

The fuel-charging opening 12 of the furf nace is normally closed by a liquid sealing pan 158 which ismounted on the inside of the shell 78. To accomplish this, the charging opening 12 is formed as the linner surface of acylinder 160 secured to a plate 162 mounted upon the upper `end of a column 164 which is supported on the shell cover 82 (Figs. 2 and 6). tween the cylinder 160 and column 164 is adapted to receive the walls of the liquidsealing pan 158 so that the lower end of the cylinder 160 will project into the liquid of the pan. The pan 158 is mounted on the outer end of a bar 166 which is ixed on a rod 168. The lower end of the rod 168 is slidably mounted in a bearing 170 Se-V by which the rod may be operated to draw the sealing panjdown from the cylinder 160 and to remove the pan from the charging opening. To permit fuel or any forei n materal which may accumulate in t 1e charging pan 158 to be removed therefrom, the pan is arranged to be tiltedv on the rod 166 to discharge suchmaterial into the fun. nace. To this end a hinge portion 177 on I the bottom of thepan is fixed onv a pivot rod 178 mounted in the arm 166. The hinge portion is near the edge of the pan so that when the pan is in upright position it will be held by gravity upon the upper side of the arm 166. The pivot rod may be rotated to tilt the pan by means of a notched disk 180 which is secured to the end of a shaft 182 journalled in abearing. 183 andv projectin through a stuffing' box 184 to the outside of the shell 78.

The fuel is charged into the furnace .by means of a transportable bucket which is arranged to .make a gas-tight seal over the charging-opening 12 while .the fuel is being charged into `the furnace. The charging bucket 186 (Fig. 6) consists ofa cylin- The space bedrical drum having a closed top 188 and a charging spout 190 which is positioned Within the drum near its central portion. The lower end of the drum constitutes a sealing flange 191 which is arranged to enter a liquid receptacle 192 surrounding the charging opening 12. When the flange 191 is in the receptacle 192, the bucket acts as a gas-seal foi-,the charging opening 12 so that the sealingf pan may be removed from the opening to permit fuel to be charged intothe furnace. The fuel is held in the bucket 186 by closing the charging spout 190 with a pair of gates 194 which are movably mounted on a track 196 secured to the flange 191. With the charging bucket in position over the charging opening 12, fuel in the bucket may be discharged into the furnace by withdrawing the gates 194 from the spout 190 by means of rods 198 which extend through packing glands 200 mounted in the ange 191.

The cokedischarging gate 14 and its operating mechanism, the coke-discharging scraper 136 and its operating mechanism, the liquid-sealing pan 158 and its operating mechanism, and the fuel-charging bucket 186, have substantially the same construction and mode of operation as the same parts which are shown and described in my copending application, Serial No. 253,- 046, tiled September 7, 1918, for coal car.- bonizing furnaces, and reference is hereby made to said application for a detail description of the construction and mode of operation of these parts.

The furnace illustrated in the present application is well adapted toL be used in conjunction with thecoal carbonizing furnace of my application, Serial No. 253,046. With this arrangement, the coal carbonizing furnace would be used for producing coke and the coke would be used in the furnace of the present application for making water-gas. If the fuel column consists entirely of coke, only three distinct zones will be maintained in the fuel column, namely, the hot midy zone through which the cross blast is forced, the coke-cooling zone extending from the hot mid zone to the bottom of the column, and a coke-preheating gas or other combustible gas andl water va' pors absorbed in` the s since the gas will act as. a carrying me ium for introducing the water vapors into the fuel column without the necessity of heating water suiiciently high to generate steam. Further, i.

the gasl of the mixture acts' as a heattransferring medium `for maintaining the distinct zones in the coke column and re'- ducesthe partial pressures at which the formation of gas may take place.

If coke'is not accessible for running the furnace illustrated i-n the drawings, this furnace may be usedfor carbonizingl coal and producing water gas. When coal is carbonized in thevfurna'ce, coal alone or a mixture of co-al with coke, the mixture depending upon the amount of volatile material in the coal, is charged into the furnace and the four distinct zones 38, 40, 42 and 44 above referred to are'maintained in the fuel column. During the gas-making operation, the air blast fan 16 is shut off, the exhaust pipes 28 and 30 are closed, and the heat-transferring gas consisting of steam or a mixture of gaswith water vapor,

is circulated up through the fuel column.

The outlet 46 and pipe 48 always remain open and during the first part of the blasting operation, the heat-transferring gasI is circulated u through the fuel column with sufficient ve ocity to hold the oils or tars.

condensed in the coal-distilling zone 42 from running back into the coal carbonizing zone 40. When the air blast is built up to full pressure, the heat-transferring gas circuit is cut off and suflicient back pressure is placed on the exhaust pipe 28 or 30 by the tes 12() and 123. to force a portion of t e blasting gas upwardly through the fuel column to prevent the tar or oil in` thecolumn from running down. into the coal carbonizing zone. When the temperature of the hot mid zonev has been built. up sufficiently for making gas, the heat-transferring gas is circulated up through the fuel column before the air blast is. entirely cpt o' to maintain the circulation of gas-'up through thecoal carbonizing and coal-distilling zones to hold the tar and oil in the upper portion of the fuel bed. In this way, gas is always being circulated upthrough the fuel column above the'hot.

mid zone to prevent tar or o il from. running down intothev coal carbonizing zone.

When carbonizing coal and producing gas, the temperature of the mid zone is 4maintained sufficiently `high to'y decompose steam and the temperaturev ofthe coal carbonizing zone is maintained sufficiently high to decompose pitches distilled from the coal so that practically all of the heavytars and pitches which condense in' the coal-distil-S ling zone and run back into the coal carbonizing zone, are broken-up into fixed introduce the vapor' into t gases and free carbon rlhel heat-transfer-` ring gas used when carbonizing coal preferably consists of a mixture of watervapor -and water gas, or any other combustible as which will not be decomposed in passing through the hot mid zone. ln this way, the, water gas acts as a' carriying medium to e fuel bed for making water gas and avery large amount 'combustion supporting gas produce amid zone ofv sufficiently high tem-l of coal can be" carbonized for producing coke. lf they water produced in the operation, however, contains .coal-distillation products Vwhich will be decomposed by passing them through the hot l mid zone 38, itmay be desirable to introduce steam alone at the base of the fuel column as a heatcarrying medium. J rll`he temperatures of the fuel column are so regulated that the gases leaving the top of the furnace will haveonlysufiicient temperature to carry olf -steam and other low boiling products. rllhe heat of these gases, however, is not lostsince they heat up the water of the condenser 50 and the heated water is utilized in the absorber 70. The, word steam used in the claims as referring toa heat-transferring gas or a component of a heat-transferring gas, is intended to include Water vapor which may be. absorbed ina gas. Y The preferred form of the invention having been thusfdescribed,.what is .claimed as new 1s:

1. A process of producing combustible gas comprising,supporting a column of fuel in a shaft furnace, intermittently blasting a transversely through a mid portion of said column to 95, perature to decompose steam, and clrculating steam upwardly through said column between said blasting operations.

2. A process of producing combustible gas comprising, supporting a column of fuel in. a shaft furnace, intermittently blasting a combustionsupporting gas transversely through a mid portion of said column to produce a mid zone of suli'ciently high temperature to decomposeV steam, and circulating a mixture of steamand gas upwardly through said column between blasting operations. Y

.3. A process of producing combustible'gas'- comprising, continuously passing fuel asa column downwardly through -a shaft fur-x, nace, intermittently blasting a combustionsupporting gas transversely through a mid i portion of said column to produce a mid zone of suiiciently high temperature to del115 compose steam, and circulating steam longitudinally of said column between blasting. operatlons.

4. p rocess of producing combustible gas compr1s1ng,supporting a column'of fuel in 120 a shaft furnace, intermittently blasting a combustionsupporting gas transversely through a mid portion of said column to produce a mid zone of sufficiently high tem' perature to decompose steam, circulating v I 5. A process ofproducing combustible gas comprising, supporting a column of fuel in a shaft furnace, intermittently blasting a combustion-supporting gas transversely through a midI portion of said-column to produce a mid zone of sufficiently high temperature to decompose steam, circulating a mixture of gas and water vapors longitudinally of said column between blasting operations, and regulating the flow of gas through said column to maintain the upper and lower ends of the column comparatively cool.

6. A process of producing combustible gas comprising, continuously passing fuel in a column downwardly through a shaft furnace, intermittently blasting a combustionsupporting gas transversely through a mid portion of said column to produce a mid zone of sufficiently high temperature to de` compose steam, and circulating a gas longitudinally of said column between blasting operations and absorbing water vapors in said gas before introducing gas into said column.

7. A process of producing combustible gas comprising, supporting a column of fuel in a shaft furnace, intermittently circulating steam longitudinally of said column, intermittently blasting a combustion-supporting gas transversely through a mid portion of said column to produce amid zone of suiicently high temperature to decompose steam, and regenerating the heat of exhaust blast gases to introduce said blast gases into the fuel column in a heated state. f

8. A process of -producing combustible gas comprising, supporting a column of fuel in a shaft furrrace, intermittently circulating a mixture of steam and water vapors upwardly through said column, intermittently passing a combustion-supporting.gas transversely through a mid portion of said column to produce a mid zone of suficiently high temperature to decompose steam, and regeneratingthe heat of exhaust blast gases to introduce said blast gases into the fuel column in a heatedi state.

9. A process of producing combustible gas comprising, supportingI a column of fuel in a shaft furnace, intermittently blasting a combustion-supporting gas transversely through a mid portion of said column, intermittently circulating steam longitudinally of'said column, withdrawing gas from the upper portion of said furnace, cooling said gas with water, a`nd circulating steam from said water through said column.

10. A process of producing combustible gas comprising, supporting a columnof fuel in a shaft furnace, intermittently blasting the combustion-supportmg gas transversely through a mid 'portion of said column to 'produce a mid zone of sufficiently high temperature to decompose steam, intermittently circulating steam upwardly through said column, withdrawing gas from the vupper portion of said furnace, cooling said gas with water byheat interchange of 'said gas with said water while out of contact with said water,passing a4 portion of said cooled v gas through said water to absorb water gas from the upper portion of said furnace,

passing .a portion of said gas through water to absorb vapors, and circulating said gas vapor mixture upwardly through saidcolf umn.

12. A process of producing combustible gas comprising, supporting a column of fuel comprising coke in a shaft furnace, intermittently blasting afcombustion-supporting gas transversely through a mid portion of said column toproduce a mid zone of sufiiciently high temperature to decompose steam,

and circulating steam longitudinally Yof said column between blasting operations.

13. A process of producing combustible gas comprising, supporting a column of fuel comprising a mixture of coal and cokein a shaft furnace, intermittently burning a portion of said fuel by blasting an oxygencarrying gas transversely through said column to produce amid zone of suiliciently high temperature to decompose steam, and circulating steam upwardly through said' column between blasting operations.

14. A process of producing combustible" gas comprising, supporting) a column of fuel -comprising coke 1n a shaft furnace, intermittently burning a portion of said fuel by blasting an oxygen-carrying gas transversely through said column to produce a mid zoneof sufficiently high. temperature to decompose lsteam, withdrawing combustible gas from the upper end offsaid furnace, cooling said gas with water, passing a portionof said gas through said water to absorb Hvapors, and circulating said gas and vapor. mixture upwardly through said column.

15. A process of carbonizing co/al and producin gas comprising, passing a column of fuelA ownwardly through a shaft furnace, intermittently burning a portion of said fuel by blasting a combustion-supporting gas transversely through a mid portion of said column, circulating .steam upwardly through fsaid column between blasting operations, .condensing tar in said column above said mid portion, and circulating gases upwardly through said column during said blasting operationswith sufficient velocity to hold tar from running down i-nto saidl mid portion.

16. A process of carbonizing coal and producing gas comprising, passinga' column of l fuel downwardly througha shaft furnace,

intermittently burning a portion of said fuel by blasting l a combustion-Supporting gas transversely through amid portion of said column to produce -a hot mid zone, circulating steam upwardly through said column between blasting operations, condensing tar in said columnabove said mid zone, and circulating blasting gases upwardly through said column during said blasting operations with suiicient velocity to hold tar from running down into said mid zone.

17. A process of carbonizing coal and producing gas comprising, passing coal continuously 1n a column vdownwardly through a shaft furnace, intermittently blasting an oxygen-carrying gas through a mid portion of said column to produce a hot mid zone therein, circularing steam upwardly through said column between blasting operations, condensing tar in sa1d. column above sald mid zone, and clrculatmg gases upwardly through said column during said blasting revent said tar from running operation to downwardly 1n said column.

l18. A process of carbonizi-ngcoal and pro- 1 ducin gas comprising, passinga column` of fuel ownwardly through a shaft furnace, vintermittently blasting an oxygen-carrying gas transversely through said column to produce a hot midzone therein, circulating a mixture of v gas and steam upwardly through said column between blasting operasaid mid-zond and circulating gases' upwardly through said column during said tions, condensing tar in said column above .f v

blasting operations with suiicient velocity I -to holdfsaid tar from running down into said mid zone. y l

19. A process of ca rbonizing coal and producing gas -compris1ng, passing .a columny of fuel downwardly through a shaft furnace,

intermittently blasting an oxygen-carrying 'gas transversely through said column to produce a hot mid zone therein, controlling the passage of blast gases through said .column v to prevent said blast gases from direct action upon a coal carbonizing zone above said mid zone, and circulating steam upwardly vthrough said column between blasting operations.

ations, condensing tar in the upper end of` said columnand circulating gases upwardly through said column during said blasting operations with suflicient suction to hold tar from `running down into said coal carbonizing Zone. Y

In testimony whereof li affix my signature.

HENRY L. nonnnrr.

20. 4A processofcarbonizing coal and proso i 

